Removing material from defective opening in glass mold and related glass mold for injection molded solder

ABSTRACT

Methods of removing material from a defective opening in a glass mold using a laser pulse, repairing a glass mold and a related glass mold for injection molded solder (IMS) are disclosed. In one embodiment, a method includes providing a glass mold including a plurality of solder filled openings; identifying a defective opening in the glass mold; removing material from the defective opening by applying a laser pulse to the defective opening; and repairing the defective opening by filling the defective opening with an amount of solder by: removing a redundant, non-defective solder portion from an opening in the glass mold by applying a laser pulse to the opening, and placing the redundant, non-defective solder portion in the defective opening.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/014,959, filed on Jan. 16, 2008, currently pending and herebyincorporated by reference in its entirety.

BACKGROUND

1. Technical Field

The disclosure relates generally to chip package fabrication, and moreparticularly, to methods and a related mold for injection molded solder(IMS).

2. Background Art

In the integrated circuit (IC) chip packaging industry, injection moldedsolder (IMS) is a widely used process for forming structures on a wafer.IMS includes using a glass mold having numerous openings that are filledwith solder. The solder is then transferred from the openings to a waferforming structures such as controlled collapse chip connects (C4). IMSmay also be used to form a wide variety of other structures.Unfortunately, sometimes the fill process of the openings on the mold isnot perfect and there are fill related defects on the mold. Thesedefects must be repaired if a perfect wafer is to be produced.Currently, there is no automated process to correct the defects and amanual defect picking and replacement operation to repair the molds isused.

SUMMARY

Methods of removing material from a defective opening in a glass moldusing a laser pulse, repairing a glass mold and a related glass mold forinjection molded solder (IMS) are disclosed. In one embodiment, a methodincludes providing a glass mold including a plurality of solder filledopenings; identifying a defective opening in the glass mold; removingmaterial from the defective opening by applying a laser pulse to thedefective opening; and repairing the defective opening by filling thedefective opening with an amount of solder by: removing a redundant,non-defective solder portion from an opening in the glass mold byapplying a laser pulse to the opening, and placing the redundant,non-defective solder portion in the defective opening.

A first aspect of the disclosure provides a method including: providinga glass mold including a plurality of solder filled openings;identifying a defective opening in the glass mold; removing materialfrom the defective opening by applying a laser pulse to the defectiveopening; and repairing the defective opening by filling the defectiveopening with an amount of solder by: removing a redundant, non-defectivesolder portion from an opening in the glass mold by applying a laserpulse to the opening, and placing the redundant, non-defective solderportion in the defective opening.

A second aspect of the disclosure provides an injection molding solder(IMS) mold including: a plurality of a plurality of solder filledopenings; and at least one empty opening, wherein the plurality ofsolder filled openings includes at least one repaired opening filledwith a solder from the at least one empty opening.

A third aspect of the disclosure provides an injection molding solder(IMS) mold including: a plurality of solder filled openings; and atleast one empty opening, wherein the plurality of solder filled openingsincludes at least one repaired opening filled with a solder from the atleast one empty opening, wherein the at least one empty opening isformed by removing the solder from a solder filled opening in theplurality of solder filled openings, and wherein the repaired opening isfilled with the solder using a solder jetting tool.

The illustrative aspects of the present disclosure are designed to solvethe problems herein described and/or other problems not discussed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this disclosure will be more readilyunderstood from the following detailed description of the variousaspects of the disclosure taken in conjunction with the accompanyingdrawings that depict various embodiments of the disclosure, in which:

FIG. 1 shows a glass mold including defective openings.

FIGS. 2-4 show embodiments of methods of removing a defective openingand repairing a defective opening in the glass mold of FIG. 1 accordingto the disclosure.

FIG. 5 shows embodiments of a repaired glass mold according to thedisclosure.

It is noted that the drawings of the disclosure are not to scale. Thedrawings are intended to depict only typical aspects of the disclosure,and therefore should not be considered as limiting the scope of thedisclosure. In the drawings, like numbering represents like elementsbetween the drawings.

DETAILED DESCRIPTION

Methods of removing material from a defective opening in a glass moldusing a laser pulse, repairing a glass mold and a related glass mold forinjection molded solder (IMS) are disclosed. FIG. 1 shows a glass mold100 including a plurality of solder filled openings 102. In oneembodiment, glass mold 100 may be used for any now known or laterdeveloped injection molded solder (IMS) process. In one embodiment,plurality of solder filled openings 102 may include greater than onemillion openings for forming a controlled collapse chip connect (C4).However, as understood by those with skill in the art, IMS has a widevariety of applications beyond this particular case. Solder filledopenings 102 may take a variety of forms, e.g., cylindrical, square,trenches, etc. The solder may take the form of any now known or laterdeveloped solder material, e.g., tin (Sn), lead tin alloys (eutechic,97/3, 95/5), tin alloys (SnCu, SnAg, SnAgCu, and the previous with Ge orMo additives), etc. Glass mold 100 may be made of any now known or laterdeveloped mold material (e.g., borosilicate, quartz, silicon, etc.).

Glass mold 100 also includes a number of illustrative defective openings104A-104F. A defective opening may take a variety of forms such as, butnot limited to: an overfilled opening 104A, an underfilled opening 104B,a void-including opening 104C, a contaminant-including opening 104D,shorted opening(s) 104E and/or an incorrectly dimensioned opening 104Fwithin the glass (latter shown as an overly large opening). One or moreof defective openings 104A-104F may occur in any given glass mold 100.Note, the term “defective opening” is used broadly to include openingsincluding the above described problems and those having included (nowemptied of) the above described problems.

FIGS. 2-4 show embodiments of methods of removing a defective opening104 (FIG. 1) and repairing a defective opening 104 (FIG. 1) in glassmold 100 according to the disclosure. FIG. 2 shows identifying adefective opening 104 in glass mold 102. This process may be carried outusing any now known or later developed optical evaluation tool 110,e.g., Suss Microtec's Mold Inspection Tool or other commerciallyavailable pattern recognition system, capable of detecting a defectiveopening 104. The pattern recognition machine may identity each molddefect by type (missing solder, extra solder, etc.) to facilitate therepair process and mold fill process learning.

FIG. 2 also shows removing material 112 from defective opening 104(FIG. 1) by applying a laser pulse 120 to the defective opening.“Material” 112 may include solder, contaminants, parts of glass mold 100or other matter constituting or causing defective opening 104, orcombinations thereof. A vacuum 130 may be applied to capture material112 from defective opening 104. Vacuum 130 may be applied by a vacuumtip (as shown) or by a wider area application. Laser pulse 120 may beapplied using a laser system 140, which may include, for example, asolid state laser system 140 such as those available from New Wave, oran excimer laser system. Laser pulse 120 may have any wavelength capableof applying a force significant enough to remove solder from defectiveopening 104 (FIG. 1), for example, 308 nm, 532 nm, etc. Nearly anypulsed laser system with a wavelength strongly absorbed by the solderbut not by the mold material would function as part of this disclosure.Laser system 140 is configured to be positioned according to the resultsof the evaluation by optical evaluation tool 110 such that laser pulse120 passes through a back side 142 of glass mold 100 at a defectiveopening 104 (FIG. 1). Laser pulse 120 ejects material 112 of defectiveopening 104 (FIG. 1). The removal may be repeated, as shown in FIG. 2,for any number of defective openings 104 (FIG. 1), and can be automatedto make the process accurate, quick and less costly. In one embodiment,laser pulse 120 may include a plurality of laser pulses, however, thismay not be necessary in all instances.

FIG. 3A shows one embodiment of a method of repairing defective opening104 (FIG. 1) by filling the emptied defective opening with an amount ofsolder 150. In one embodiment, defective opening 104 (now empty as shownin FIG. 3) may be filled using a well-known solder jetting tool 160 suchas those available from Microfab, which fills defective opening 104 withamount of solder 150. However, in some instances, use of a solderjetting tool 160 may be difficult since different solders may be usedwithin a given fabrication setting and different amounts of solder 150may be required. In this case, solder jetting tool 160 customizationfor, among other things, each solder, presents a challenge. Furthermore,this approach does not allow for placing a correct amount of solder 150in a defective opening 104F (FIG. 1) that is constituted by an overlylarge opening in glass mold 100.

FIG. 3B shows another embodiment of a method of repairing defectiveopening 104 (FIG. 1) by filling the emptied defective opening with anamount of solder 150. In this embodiment, glass mold 100 is providedwith a number of redundant, non-defective solder portions 162 thatinclude amount of solder 150. A redundant, non-defective solder portion162 is removed from an opening 164 in glass mold 100 by applying a laserpulse 166 to the opening, i.e., through back side 142 of glass mold 100.A vacuum tip 170 may be used to carry and place redundant, non-defectivesolder portion 162 (i.e., amount of solder 150) in defective opening104. This vacuum tip would typically have an opening size approximately50% of the diameter of the mold features being repaired. In oneembodiment, shown in FIG. 4, the placing may include using a laser pulse182 to assist in forcing amount of solder 150 into defective opening104. Further, laser pulse 182 may also melt a surface 184 of redundant,non-defective solder portion 162 (i.e., amount of solder 150), whichassists in adherence of amount of solder 150 in the opening. The same ordifferent laser system 140 may be used for removing material 112 (FIG.2), removing solder portion 162 (FIG. 3B) or placing amount of solder150 (FIG. 4).

The repair process of either FIG. 3A or 3B can be automated to make theprocess accurate, quick and less costly.

FIG. 5 shows a repaired mold 200 for IMS including a plurality of aplurality of solder filled openings 102, and at least one empty opening204 (from removal of solder portion 162). Solder filled openings 102include at least one repaired opening 202 filled with a solder (i.e.,amount of solder 150) from the at least one empty opening 164. Asillustrated by repaired opening 202, the repair process using redundant,non-defective openings 162 (FIG. 3B) described above allows for thecorrect amount of solder 150 to be placed in defective opening 104F(FIG. 1), despite a defect in the form of an overly large opening inglass mold 100.

The foregoing description of various aspects of the disclosure has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the disclosure to the precise formdisclosed, and obviously, many modifications and variations arepossible. Such modifications and variations that may be apparent to aperson skilled in the art are intended to be included within the scopeof the disclosure as defined by the accompanying claims.

1. An injection molding solder (IMS) mold comprising: a plurality of solder filled openings; and at least one empty opening, wherein the plurality of solder filled openings includes at least one repaired opening filled with a solder from the at least one empty opening.
 2. The IMS mold of claim 1, wherein the at least one empty opening is formed by removing the solder from a solder filled opening in the plurality of solder filled openings.
 3. The IMS mold of claim 1, wherein the repaired opening is filled with the solder using a solder jetting tool.
 4. An injection molding solder (IMS) mold comprising: a plurality of solder filled openings; and at least one empty opening, wherein the plurality of solder filled openings includes at least one repaired opening filled with a solder from the at least one empty opening, wherein the at least one empty opening is formed by removing the solder from a solder filled opening in the plurality of solder filled openings, and wherein the repaired opening is filled with the solder using a solder jetting tool. 